C2: assert(in_vt->length() == out_vt->length()) failed: mismatch on number of elements

jdk/incubator/vector/VectorHash.java crashes with

# Internal Error (/opt/mach5/mesos/work_dir/slaves/983c483a-6907-44e0-ad29-98c7183575e2-S14654/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/70c30587-cac3-4c43-9da3-b32db79c2936/runs/6b7ce9ab-a517-4ec4-a27f-80b4479d4067/workspace/open/src/hotspot/share/opto/vectornode.cpp:1224), pid=24921, tid=24937
# assert(in_vt->length() == out_vt->length()) failed: mismatch on number of elements
#
# JRE version: Java(TM) SE Runtime Environment (17.0) (fastdebug build 17-internal+0-LTS-2021-01-07-1759264.ekaterina.pavlova.panama-vector)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 17-internal+0-LTS-2021-01-07-1759264.ekaterina.pavlova.panama-vector, compiled mode, sharing, compressed oops, g1 gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0x19657ce] VectorUnboxNode::Ideal(PhaseGVN*, bool)+0x11e

The crash occurred when running the test with following stress flags:
 -ea -esa -Xcomp -XX:CompileThreshold=100 -XX:+UnlockExperimentalVMOptions -server -XX:-TieredCompilation -XX:+DeoptimizeALot

The issue is seen only in panama-vector repository (master branch).
No crash is seen in jdk16 or latest jdk bits.

To run the test do:
> jtreg -timeoutFactor:40 -jdk:build/linux-x64/images/jdk
 -vmoptions:"-Xmx512m -Xcomp -ea -esa -XX:CompileThreshold=100 -XX:+UnlockExperimentalVMOptions" -server -XX:-TieredCompilation -XX:+DeoptimizeALot"
 -dir:test/jdk jdk/incubator/vector/VectorHash.java